> “A class should have one, and only one, reason to change”
```python
import numpy as np
def math_operations(list_):
# Compute Average
print(f"the mean is {np.mean(list_)}")
# Compute Max
print(f"the max is {np.max(list_)}")
math_operations(list_ = [1,2,3,4,5])
# the mean is 3.0
# the max is 5
```
Having a single function do all the work is a bad approach
split the function `math_operations` into atomic functions
Make a single function (or class), generically named, "main". This will call all the other functions one-by-one in a step-to-step process.
```python
def get_mean(list_):
'''Compute Mean'''
print(f"the mean is {np.mean(list_)}")
def get_max(list_):
'''Compute Max'''
print(f"the max is {np.max(list_)}")
def main(list_):
# Compute Average
get_mean(list_)
# Compute Max
get_max(list_)
main([1,2,3,4,5])
# the mean is 3.0
# the max is 5
```
The result of this simple action is that now:
- It is easier to localize errors. Any error in execution will point out to a smaller section of your code, accelerating your debug phase.
- Any part of the code is reusable in other section of your code.
- Moreover and, often overlooked, is that it is easier to create testing for each function of your code.
- _Side note on testing:_ You should write tests before you actually write the script. But, this is often ignored in favor of creating some nice result to be shown to the stakeholders instead.
---
- Reference:
- [[( 2021-11-10 Solid Coding in Python]]